EA020426B1 - Purification of alcohols prior to their use in the presence of an acid catalyst - Google Patents

Abstract

Process for the purification of an alcohol in the course of a process comprising : (1) providing a reaction zone (C) comprising an acid type catalyst; (2) providing a reaction zone (B) comprising an acid adsorbent material; (3) providing an alcohol stream comprising impurities; (4) introducing the alcohol stream of (3) into the reaction zone (B) and bringing said stream into contact with the acid adsorbent material at conditions effective to reduce the amount of impurities having an adverse effect on the acid type catalyst of the reaction zone (C); (5) recovering from step (4) an alcohol stream and introducing it into the reaction zone (C); (6) optionally introducing one or more reactants (R) into the reaction zone (C); (7) operating said reaction zone (C) at conditions effective to recover a valuable effluent.

Description

This invention relates to the purification of alcohols before their use in the presence of an acid catalyst. Such use is, for example, the esterification of isobutene and isoamylenes with ethanol to produce ETBE (ethyl tert-butyl ether) and ETAE (ethyl tert-amyl ether), self-esterification or dehydration of alcohols to produce olefins. The limited supply and rising cost of crude oil prompts the search for alternative methods for producing hydrocarbon products such as fuels and ethylene. Ethanol can be obtained by fermentation of carbohydrates. Consisting of the organic matter of living organisms, biomass is the world's main renewable energy source. Dehydration is carried out in the presence of a catalyst, such as alumina or silica-alumina. This method works well with substantially pure ethanol, such as ethanol, coming from a distillation or dehydration step through molecular sieves by adsorption, but this distillation step or adsorption step requires a lot of energy. On the other hand, the use of crude ethanol leads to poisoning of the acid catalyst. The present invention relates, in one embodiment, to a method for purifying a crude alcohol that does not require a lot of energy and prevents acid catalyst poisoning.

BACKGROUND OF THE INVENTION

Dehydration of alcohols is described in the prior art. US patent 4207424 describes a method for the catalytic dehydration of alcohols to form unsaturated organic compounds in which the alcohol is dehydrated in the presence of alumina catalysts that are pretreated with an organic silylating agent at elevated temperature. US 4302357 relates to an activated alumina catalyst used in a method for producing ethylene from ethanol by a dehydration reaction. In the description of LH8U (hourly space velocity of the liquid) of ethanol is from 0.25 to 5 h ^-1 and preferably from 0.5 to 3 h ^-1 . Examples are carried out at 370 ° C and LH8U 1 h ^-1 , the ethylene yield is from 65 to 94%. US patent 4232179 relates to the preparation of ethylene based on the method of dehydration of ethyl alcohol. More specifically, the purpose of this known solution is to produce ethylene in the presence of catalysts using adiabatic reactors and high temperature. Such adiabatic reactors can be used in parallel or can be installed in series, or installed in blocks of parallel sequences, or only one reactor can be used. European patent 22640 relates to improved zeolite catalysts, methods for producing such catalysts and their use in the conversion of ethanol and ethylene to liquid and aromatic hydrocarbons, including the conversion of ethanol to ethylene. US Pat. No. 4,727,214 relates to a process for converting anhydrous or aqueous ethanol to ethylene, wherein at least one crystalline zeolite type catalyst is used, said catalyst having, on the one hand, channels or pores formed by rings or rings of oxygen atoms having 8 and / or 10 elements or members. US Pat. No. 4,847,223 describes a catalyst comprising from 0.5 to 7% by weight of trifluoromethanesulfonic acid included in an acid form of a pentasil type zeolite having an atomic ratio of δί to A1 in the range of 5 to 54, and a method for producing it. Also within the scope of this known solution is a method for converting dilute aqueous ethanol to ethylene. US Pat. No. 4,873,392 describes a process for converting dilute ethanol to ethylene, which comprises heating an ethanol-containing fermentation broth to evaporate a mixture of ethanol and water and contacting said evaporated mixture with a ΖδΜ-5 zeolite catalyst.

Nitriles are present in trace amounts in olefin hydrocarbon fractions produced at the refinery, since there are PCC (cracking with a fluidized catalyst) and cracking furnaces for easy cracking. Such nitriles tend to concentrate in a more polar stream, since there is a methanol stream in the ΜΤΒΕ block (methyl tert-butyl ether). Unconverted methanol enriched with nitriles is recycled back to the esterification reactor and leads to increased poisoning of the acid esterification catalyst.

\ νϋ 1997045392 provides an improved esterification process that reduces the amount of acid catalyst from an ion exchange resin that is deactivated by nitriles. This method uses an aqueous phase to remove nitriles from the hydrocarbon phase, followed by an alcohol phase to remove nitriles from the aqueous phase. The hydrogenation catalyst is used to convert nitriles to amines so that they can be more easily removed from the alcohol phase.

European patent 1176132 relates to a method for esterification of olefins, comprising contacting in a reaction zone in which an acid type catalyst is present and in which the prevailing conditions are suitable for the esterification reaction of at least one alcohol and a hydrocarbon charge rich in light olefins, but containing nitrogen compounds, who are responsible for the deactivation of the catalyst;

separating the effluent from the reaction zone to obtain at least one first fraction rich in ether and a second fraction containing the main part of the residual alcohol and including nitrogen compounds; and recycling the second fraction to the entrance of the reaction zone; moreover, this method is characterized by the fact that before recycling to the reaction zone, the second fraction is subjected to a treatment comprising at least one step of bringing into contact with an acidic adsorbent material to reduce the concentration of said nitrogen-containing compounds by at least 50% .

Advantageously, the acidic adsorbent material is selected from the group formed by microscopic aluminosilicates such as silicalites, mordenites, X zeolites and preferably Υ zeolites, macroreticular resins grafted with acidic groups (e.g. sulfonic acid), silica impregnated with acid (e.g. phosphoric acid or sulfuric acid), activated carbon, unmodified or impregnated with an acid (e.g. phosphoric acid or sulfuric acid), activated alumina;

clays unmodified or treated with acid, molecular sieves, crystalline and microporous aluminophosphates, mesoporous aluminosilicates.

Advantageously, before contacting with the acidic adsorbent material, the second fraction undergoes a hydrogenation phase that is selective for the nitrogen containing compounds it contains.

These two known solutions described above relate only to the esterification process, describe only the removal of nitrile components that come from olefinic hydrocarbon streams, and concern only methanol, in which nitriles are concentrated.

Of great interest is the use of alcohols from biomass. The use of crude alcohols is of interest to avoid the expensive steps of further distillation, dehydration by adsorption or purification. With regard to dehydration, it is performed in the presence of a catalyst, such as alumina or silica-alumina. This method works well with substantially pure ethanol, such as ethanol coming from a distillation step or a dehydration step through molecular sieves by adsorption, but this distillation or adsorption step requires a lot of energy. On the other hand, the use of crude ethanol leads to poisoning of the acid catalyst. The crude ethanol was found to contain impurities that are poisons of a dehydration catalyst or an esterification catalyst.

The present invention relates in one embodiment to a process for purifying a crude alcohol that does not require a lot of energy and prevents poisoning of the dehydration catalyst.

SUMMARY OF THE INVENTION

The present invention consists in a method for purifying alcohol during a process comprising:

(1) providing a reaction zone (C) comprising an acid type catalyst;

(2) providing a reaction zone (B) comprising a sorbent material or a combination of sorbent materials;

(3) providing an alcohol stream including impurities;

(4) introducing the alcohol stream (3) into the reaction zone (B) and bringing said stream into contact with the adsorbent material under conditions effective to reduce the amount of impurities adversely affecting the acid type catalyst of the reaction zone (C);

(5) recovering the alcohol stream from step (4) and introducing it into the reaction zone (C);

(6) optionally introducing one or more reagents (K) into the reaction zone (C);

(7) operating said reaction zone (C) under conditions effective to restore valuable effluent.

In an embodiment, the impurities are selected from the group consisting of nitriles, aldehydes, ketones, carboxylic acids, carboxylic acid esters, amides, and corresponding thio compounds and imines.

According to a specific embodiment, the impurities are selected from the group consisting of

K — C in which K is a hydrocarbyl moiety or hydrogen (nitriles are an example), and

K1 \

c = x /

K2 in which X is oxygen, sulfur, K1 is the hydrocarbyl part, K2 is the hydrocarbyl part, hydrogen, hydroxyl part, amine part or alkoxy part (examples are aldehydes, ketones, carboxylic acids, esters of carboxylic acids, amides and the corresponding thio compounds), and

- 2 020426 in which K1 is the hydrocarbyl part or hydrogen, and K2 is the hydrocarbyl part, hydrogen, hydroxyl part or alkoxy part (imines are examples).

According to an embodiment, only a portion of the alcohol stream of step (3) is processed in step (4), mixed with the untreated portion and introduced into the reaction zone (C).

According to an embodiment, before step (4), the alcohol stream of step (3) is introduced into the reaction zone (A) including the hydrogenation catalyst and is contacted with said catalyst in the presence of hydrogen under conditions effective (ί) to convert some or all of the impurities to modified impurities that can remain on the acidic adsorbent material of the reaction zone (B), or (ίί) to convert part or all of the impurities into modified impurities that do not adversely affect the acid-type catalyst onnoy zone (C), or for (ί), and (ίί). According to an embodiment, only part of the alcohol stream of step (3) is processed in the reaction zone (A), mixed with the untreated part and introduced into the reaction zone (B).

According to an embodiment, the acidic adsorbent material in the reaction zone (B) also functions as a hydrogenation catalyst. By way of example, it is a resin of the type Abl1u51®. υδΥ (ultra-stable zeolite Υ) or mesoporous silica-alumina impregnated with Ρά, Ρΐ, Co, Mo or Νΐ. This means that zone (A) is absent and that in the specified zone (B) the alcohol stream is brought into contact with the specified catalyst in the presence of hydrogen under conditions effective (ί) to convert some or all of the impurities into modified impurities that can remain in the specified catalyst the reaction zone (B), or (для) for the conversion of part or all of the impurities into modified impurities that do not adversely affect the acid type catalyst of the reaction zone (C), or both (ί) and (ίί). According to an embodiment, only part of the alcohol stream of step (3) is processed in the reaction zone (B), mixed with the untreated part and introduced into the reaction zone (C).

According to an embodiment, the reaction zone (C) provides for the dehydration of alcohol.

According to an embodiment, the reaction zone (C) provides for the esterification of an olefin, wherein the reagent (K) of step (6) is said olefin.

According to an embodiment, the reaction zone (C) provides for the self-esterification of alcohol.

Without going into any theory, it is believed that the Ν atoms bonded to C atoms via double or triple bonds are easily hydrolyzed in the presence of water or alcohols to produce amines, ammonia, or ammonium cations that neutralize the acid catalyst used in the reaction zone ( C), and it is also believed that O atoms or atoms 8 bonded to C atoms via double bonds are easily converted by condensation reactions, therefore, create heavier organic compounds, which subsequently leads to the deposition of coke basic compounds on the surface of the acid catalyst of the reaction zone (C). The hydrogenation step in the reaction zone (A) converts the double bonds existing between N and C, O and C, or 8 and C, into the corresponding single bonds (amines, hydroxyl part, alkoxy part, thiol or thiocarbyl part or corresponding decomposition products). The main amines are subsequently adsorbed on the acidic adsorbent material in the reaction zone (B), while other hydrogenated compounds with hydroxyl, alkoxy or thiol or thiocarbyl parts no longer have an adverse effect on the acid catalyst used in the reaction zone (C).

DETAILED DESCRIPTION OF THE INVENTION

As for the adsorbent material of the reaction zone (B), it can be selected from the group consisting of microporous aluminosilicates such as silicalites, mordenites, X zeolites, and preferably Υ zeolites, macroreticular grafts grafted with acidic groups (e.g. sulfonic acid), highly acidic ion exchange resins capable of exchanging anions (e.g. macromatic resins grafted with quaternary amines), acid-impregnated silicon dioxide (e.g. phosphoric acid or sulfuric acid) activated charcoal, unmodified or impregnated with an acid (e.g. phosphoric acid or sulfuric acid), activated alumina;

unmodified or acid-treated clays, molecular sieves, crystalline and microporous aluminophosphates, mesoporous aluminosilica.

The acidic adsorbent material of the reaction zone (B) may be either one of the aforementioned solids, or also a combination of the aforementioned.

The above acid adsorbents can be easily reduced by heating at about

400 ° C or ion exchange with acidic aqueous solutions.

As for the alcohol stream and the dehydration method, the alcohol is any alcohol, provided that it can be dehydrated to the corresponding olefin. An example would be

- 3,020,426 mentioned alcohols having from 2 to 10 carbon atoms. Advantageously, this invention is of interest for ethanol, propanol, butanol and phenylethanol. The alcohol stream may include an inert component. An inert component is any component, provided that it does not adversely affect the dehydration catalyst. Since dehydration is endothermic, an inert component can be used to add energy. As examples, the inert component is selected from saturated hydrocarbons having up to 10 carbon atoms, naphthenes, nitrogen, water and CO ₂ .

As for the alcohol stream and another method, it may be ethanol, methanol, 1-amyl alcohol.

As for impurities, ammonia and amines can be adsorbed on the adsorbent of the reaction zone (B). Nitriles (e.g. acetonitrile) to be hydrogenated must be converted to modified impurities capable of being adsorbed. Aldehydes, ketones, carboxylic acids and esters are hydrogenated to types that do not adversely affect the catalyst of the reaction zone (C).

As for the hydrogenation catalyst of the reaction zone (A), in fact, it is known. Mention may be made of Ρί, Py, Νί, Co, Mo and mixtures with them on any carrier such as coal, zeolites, molecular sieves, silica or alumina. Mostly it is Pb on carbon or activated carbon. Such catalysts are described in European patent 1176132, the contents of which are included in this invention.

The hydrogenation steps are carried out at a reaction temperature from 0 to 200 ° C at a pressure of 1 to 100 bar and a ratio of H ₂ to nitrogen from 1 to 1000 mol / atom Ν, and a ratio of H ₂ to carbonyl or thionyl from 1 to 1000 mol / atom O or 8.

As for the reaction zone (C) and the esterification catalyst, in fact, this is known. The esterification with alcohols with 2 or more carbons can be carried out on acid sulfonated macroporous organic ion-exchange resins in the liquid phase at a reaction temperature of from 30 to 120 ° C. The reaction can be carried out in standard fixed bed reactors, fluidized-bed reactors, or in catalytic distillation columns including an acid catalyst zone.

Regarding the reaction zone (C) and the dehydration catalyst, the reaction zone may be a fixed bed reactor, a moving bed reactor, or a fluidized bed reactor. A typical liquid bed reactor is a PCC type reactor used for catalytic fluidized bed cracking in an oil refinery. A typical moving bed reactor belongs to the type of continuous catalytic conversion. Dehydration can be carried out continuously in the configuration of fixed bed reactors using a pair of parallel reactors operating on the principle of efficiency. The dehydration method is to be carried out continuously in two parallel reactors operating on the principle of efficiency, where, when one reactor is operated, the catalyst is restored in the other reactor. Dehydration of alcohol is, in fact, known. As for the catalyst, it can be any acid catalyst capable of causing dehydration of ethanol under the above conditions. As an example, zeolites, modified zeolites, silica-alumina, alumina, silica-aluminophosphates can be mentioned. Examples of such catalysts are mentioned in the above-described prior art.

According to a first advantageous embodiment, the dehydration catalyst is a crystalline silicate containing predominantly at least one 10-membered ring in the structure. As an example, these are MP1 (Ζ8Μ-5, silicalit-1, boralite C, T8-1), ME (Ζ8Μ-11, silicalit-2, boralit Ό, T8-2, 88Ζ-46), PEK (ferrierite, RI- 9, Ζ8Μ-35), MTT (Ζ8Μ-23), МАА (МСМ-22, Р8Н-3, ГГр-1, МСМ-49), ТΟN ^ 8М-22, ТЬе1а-1, Νυ-10), ЕИО ^ 8M-50, EI-1), MP8 ^ 8M-57) and Ζ8Μ-48 are a family of microporous materials, including silicon, aluminum, oxygen and, optionally, boron. Advantageously, in said first embodiment, the catalyst is a crystalline silicate with a ratio of 8ί to A1 of at least about 100 or dealuminated crystalline silicate.

Crystalline silicate with a ratio of 8ί to A1 of at least about 100, preferably selected from MRH and ME.

Crystalline silicate with a ratio of 8ί to A1 of at least about 100 and dealuminated crystalline silicate are substantially in the H-form. This means that a small part (less than about 50%) can carry metal compensating ions, for example, Να, Md, Ca, Ba, Νί, Ce, Ζη, Co.

The dealuminated crystalline silicate, advantageously comprising approximately 10% by weight of aluminum, is removed. Such dealumination is preferably carried out by steaming, optionally followed by leaching. A crystalline silicate with a ratio of 8ί to A1 of at least about 100 can be synthesized as such or it can be obtained by dealumination of a crystalline silicate under conditions effective to obtain a ratio of δί to A1 of at least about 100. Such dealumination is preferably carried out by steaming optionally followed by leaching.

Each of the three-letter designations MP and ME represents a specific type of structure of crystalline silicate, as established by the Commission on the structure of the International Association of Zeolites.

Examples of crystalline silicate of type MP are synthetic zeolite ΖδΜ-5, silicalite and other crystalline silicates of type MP known in the art. Examples of crystalline silicate of the ME family are zeolite ΖδΜ-11 and other crystalline silicates of the ME type known in the art. Other examples are boralite Ό and silicalite2, as described by the International Zeolite Association (ADAC ίί ί со Ш 81 81 г ис 1 1 урс урс урс 1. Preferred crystalline silicates have pores or channels defined by ten-oxygen rings and a high atomic ratio of silicon to aluminum.

Crystalline silicates are microporous crystalline inorganic polymers based on the framework of XO ₄ tetrahedra connected to each other by joint oxygen ions, where X can be trivalent (e.g. A1, B, ...) or tetravalent (e.g. Ce, δί, ... ) The crystalline structure of crystalline silicate is determined by a specific order, which is a network of tetrahedral units linked together. The pore size of crystalline silicate is determined by the number of tetrahedral units or, alternatively, oxygen atoms needed to form the pores, and the nature of the cations present in the pores. They have a unique combination of the following qualities: high internal surface area; homogeneous pores with one or more discrete sizes; ionic interchangeability; good thermal stability and the ability to adsorb organic compounds. Since the pores of such crystalline silicates are similar in size to many organic molecules of particular interest, they regulate the input and output of reagents and products, which leads to special selectivity of catalytic reactions. Crystalline silicates with an MP structure have a bi-directional system of overlapping pores with the following pore diameters: direct channel along [010]: 0.53-0.56 nm and sinusoidal channel along [100]: 0.51-0.55 nm. Crystalline silicates with a ME structure have a bi-directional system of overlapping straight pores with straight channels along [100], having pore diameters of 0.530.54 nm.

In this description, the expression atomic ratio of silicon to aluminum or the ratio of silicon to aluminum means the atomic ratio δί to A1 of the entire material, which can be determined by chemical analysis. In particular, for crystalline silicate materials, the established δί to A1 ratios apply not only to the δί / Λ1 framework of crystalline silicate, but rather to the entire material.

In a specific embodiment, the catalyst preferably has a high atomic silicon to aluminum ratio of at least about 100, preferably more than about 150, more preferably more than about 200, whereby the catalyst has a relatively low acidity. The acidity of the catalyst can be determined by the amount of residual ammonia in the catalyst after contact of the catalyst with ammonia, which is adsorbed to the acid sites on the catalyst, followed by desorption of ammonia at elevated temperature, as measured by differential thermogravimetric analysis. Preferably, the ratio of silicon to aluminum (δί to A1) is in the range of from about 100 to about 1000, most preferably from about 200 to about 1000. Such catalysts are essentially known.

In a specific embodiment, crystalline silicate is steamed to remove aluminum from the crystalline silicate skeleton. The steam treatment is carried out at an elevated temperature, preferably in the range from 425 to 870 ° C., more preferably in the range from 540 to 815 ° C., at atmospheric pressure and at an aqueous partial pressure of 13 to 200 kPa. Preferably, the steam treatment is carried out in an atmosphere comprising from 5 to 100% steam. The vapor atmosphere preferably contains from 5 to 100 vol.% Steam and from 0 to 95 vol.% Inert gas, preferably nitrogen. A more preferred atmosphere includes 72 vol.% Steam and 28 vol.% Nitrogen, i.e. 72 kPa of steam at a pressure of one atmosphere. The steam treatment is preferably carried out for a period of from 1 to 200 hours, more preferably from 20 to 100 hours. As indicated above, the steam treatment serves to reduce the amount of tetrahedral aluminum in the crystalline silicate framework by forming alumina.

In a more specific embodiment, the crystalline silicate catalyst is dealuminated with steam heating to remove aluminum from the crystalline silicate skeleton and extracting aluminum from the catalyst by contacting the catalyst with an aluminum complexing agent to remove the skeleton of aluminum oxide deposited therein during the steaming step, which thereby increasing the atomic ratio of silicon to aluminum in the catalyst. A catalyst having a high atomic ratio of silicon to aluminum for use in the catalytic process of this invention is produced by removing aluminum from a commercial

- 5,020,426 available crystalline silicate. As an example, a typical commercially available silicalite has an atomic ratio of silicon to aluminum of about 120. According to this invention, a commercially available crystalline silicate is modified by a steaming method that reduces tetrahedral aluminum in a crystalline silicate framework and converts aluminum atoms to octahedral aluminum in the form of amorphous alumina . Although aluminum atoms are chemically removed from the structure of the crystalline silicate framework during the steaming step to form aluminum oxide particles, these particles partially block the pores or channels in the framework. This may slow down the dehydration method of the present invention. Therefore, after the steaming step, crystalline silicate is subject to a recovery step, where amorphous alumina is removed from the pores and the micropore volume is at least partially restored. Physical removal by the step of leaching amorphous alumina from the pores by forming a water-soluble aluminum complex provides the complete dealumination effect of crystalline silicate. In this method, by removing aluminum from the crystalline silicate skeleton and then removing the aluminum oxide formed there from the pores, the method aims to achieve substantially uniform dealumination across all pore surfaces of the catalyst. This reduces the acidity of the catalyst. The decrease in acidity ideally occurs substantially uniformly across all pores defined in the crystalline silicate framework. After steam treatment, an extraction method is carried out in order to dealuminate the catalyst by leaching. Aluminum is preferably recovered from crystalline silicate with a complexing agent, which tends to form a soluble complex with alumina. The complexing agent is preferably in its aqueous solution. The complexing agent may include an organic acid such as citric acid, formic acid, oxalic acid, tartaric acid, malonic acid, succinic acid, glutaric acid, adipic acid, maleic acid, phthalic acid, isophthalic acid, fumaric acid, nitrile tri-acetic acid, hydroxyethylenediamine , ethylenediaminetetraacetic acid, trichloroacetic acid, trifluoroacetic acid or a salt of such an acid (e.g., sodium salt), or a mixture of two or more acids or salts. The complexing agent may include an inorganic acid, such as nitric acid, halogen-containing acids, sulfuric acid, phosphoric acid or salts of such acids, or a mixture of such acids. The complexing agent may also include a mixture of such organic and inorganic acids or their corresponding salts. The complexing agent for aluminum preferably forms a water-soluble complex with aluminum and, in particular, removes aluminum oxide, which is formed during the step of steaming from crystalline silicate. A particularly preferred complexing agent may include an amine, preferably ethylenediaminetetraacetic acid (ΕΌΤΛ) or a salt thereof, in particular its sodium salt. In a preferred embodiment, the ratio of silicon to aluminum in the framework is increased by this method to a value of from about 150 to 1000, more preferably at least 200.

After the aluminum leaching step, the crystalline silicate can be subsequently washed, for example, with distilled water, and then dried, preferably at an elevated temperature, for example, about 110 ° C.

In addition, if alkali or alkaline earth metals were used in the preparation of the catalysts of this invention, the molecular sieve may undergo an ion exchange step. Typically, ion exchange is carried out in aqueous solutions using ammonium salts or inorganic acids.

After the dealumination step, the catalyst is calcined, for example, at a temperature of from 400 to 800 ° C. at atmospheric pressure for 1 to 10 hours.

In another specific embodiment, the crystalline silicate catalyst is mixed with a binder, preferably an inorganic binder, and is given the desired shape, for example granules. The binder is selected resistant to temperature and other conditions used in the dehydration method of the present invention. A binder is an inorganic material selected from clays, silica, metal silicate, metal oxides such as ΖτΟ ₂ , and / or metals, or gels, including mixtures of silicon dioxide and metal oxides. Preferably, the binder is free of alumina. If the binder used in binding to crystalline silicate itself is catalytically active, it can alter the conversion and / or selectivity of the catalyst. Inactive binder materials can suitably serve as diluents to control the amount of conversion so that products can be prepared economically and appropriately without the use of other means to control the reaction rate. It is desirable to provide a catalyst having good crush resistance. This is because in commercial use, it is desirable to prevent the destruction of the catalyst to powder materials. So clay or oxide binders are usually used only for the purpose of improving the crush resistance of the catalyst. A particularly preferred binder for the catalyst of this invention includes silicon dioxide. The relative proportions of finely ground crystalline

- 6,020,426 of the silicate material and the inorganic oxide matrix of the binder can vary widely. Typically, the binder content is in the range of 5 to 95% by weight, more typically 20 to 50% by weight of the weight of the composite catalyst. Such a mixture of crystalline silicate and inorganic oxide binder is correlated with the composed crystalline silicate. By mixing the catalyst with a binder, the catalyst can be granulated, extruded into other forms, or formed into spheres or spray dried powder. Typically, a crystalline silicate binder and catalyst are mixed together by a mixing method. In this method, a binder, for example, silica, in the form of a gel is mixed with a crystalline silicate catalyst material, and the resulting mixture is extruded into the desired shape, for example, cylindrical or multifaceted bars. Spherical forms can be obtained in rotating granulators or by the technique of oil droplets. In addition, small spheres can be obtained by spray drying a suspension of catalyst and binder. After this, the crystalline silicate formed is calcined in air or an inert gas, typically at a temperature of 200 to 900 ° C. for 1 to 48 hours. The binder preferably does not contain any aluminum compounds such as alumina. This is because, as mentioned above, the preferred catalyst for use in this invention is dealuminated to increase the ratio of silicon to aluminum crystalline silicate. The presence of alumina in the binder leads to an excess of alumina if the binding step is carried out prior to the aluminum extraction step. If the aluminum-containing binder is mixed with the crystalline silicate catalyst after aluminum is recovered, it is re-dealuminated.

In addition, mixing the catalyst with a binder can be performed either before or after the steps of steaming and recovery.

According to a second preferred embodiment, the dehydration catalyst is a crystalline silicate catalyst having a monoclinic structure, which is obtained by a method comprising providing crystalline silicate of type ΜΡΙ with an atomic ratio of silicon to aluminum below 80; treating crystalline silicate with steam, and then leaching aluminum from the zeolite by contact with an aqueous leach solution to provide an atomic ratio of silicon to aluminum in the catalyst of at least 180, resulting in a monoclinic structure.

Preferably, in the steam treatment step, the temperature is from 425 to 870 ° C., more preferably from 540 to 815 ° C., with a partial pressure of water of 13 to 200 kPa.

Preferably, the aluminum is removed by leaching to form a water-soluble compound by contacting the zeolite with an aqueous solution of a complexing agent for aluminum, which serves to form a soluble complex with aluminum oxide.

According to this preferred method for producing monoclinic crystalline silicate, the ΜΡΙ type crystalline silicate starting catalyst has orthorhombic symmetry and a relatively low atomic ratio of silicon to aluminum, which can be synthesized without any organic matrix molecule, and the final crystalline silicate catalyst has a relatively high atomic ratio silicon to aluminum and monoclinic symmetry as a result of successive steam treatment and removal of al minum. After the aluminum removal step, crystalline silicate may be subject to ion exchange with ammonium ions. It is known in the art that such ΜΡΙ type crystalline silicates exhibiting orthorhombic symmetry are in the Ppt space group. The X-ray diffraction diagram of such an orthorhombic structure has one peak at D = about 0.365 nm, D = about 0.305 nm and D = about 0.300 nm (see EP-A-0146524).

The initial crystalline silicate has an atomic ratio of silicon to aluminum below 80. A typical ΖδΜ-5 catalyst comprises 3.08 wt.% A1 ₂ O ₃ , 0.062 wt.% Ν α ₂ Ο and is 100% orthorhombic. Such a catalyst has an atomic ratio of silicon to aluminum of 26.9.

The steam treatment step is performed as explained above. Steaming serves to reduce the amount of tetrahedral aluminum in the crystalline silicate framework by forming alumina. The step of leaching or recovering aluminum is performed as explained above. At the stage of leaching aluminum, crystalline silicate is immersed in an acidic solution or a solution containing a complexing agent, and then it is preferably heated, for example, heated under conditions of reverse current (at a boiling point with the complete return of condensed vapors), for a long time, for example, 18 hours After the aluminum leaching step, the crystalline silicate is washed, for example, with distilled water, and then dried, preferably at an elevated temperature, for example, about 110 ° C. Optionally, crystalline silicate undergoes ion exchange with ammonium ions, for example, immersion of crystalline silicate in an aqueous solution of ΝΗ ₄ Ο 1.

In the end, the catalyst is calcined at elevated temperature, for example at a temperature of at least 400 ° C. The calcination period typically lasts about 3 hours.

The resulting crystalline silicate has monoclinic symmetry, being in

- 7 020426 to the space group Ρ2ι / η. The X-ray diffraction diagram of the monoclinic structure shows three double peaks at 6 = about 0.36, 0.31 and 0.19 nm. The presence of such double peaks is unique for monoclinic symmetry. More specifically, the double peak at 6 = about 0.36 includes two peaks: one at 6 = 0.362 nm and one at 6 = 0.365 nm. Conversely, the orthorhombic structure has a single peak at 6 = 0.365 nm.

The presence of a monoclinic structure can be quantified by comparing the intensity of the X-ray diffraction line at 6 = about 0.36 nm. When mixtures of crystalline silicates ΜΡΙ with a pure orthorhombic and pure monoclinic structure are produced, the composition of the mixtures can be expressed as the monoclinic index (ίη%). X-ray diffraction diagrams were recorded, and the peak heights at 6 = 0.362 nm for monoclinicity and 6 = 0.365 nm for orthorhombicity were measured and denoted 1t and Ιο, respectively. The linear regression line between the monoclinicity index and 1t / 1o gives the dependence necessary for measuring the monoclinicity of unknown samples. Thus, the monoclinic index is% = (a x 1m / 1o-b) x 100, where a and b are the regression parameters.

Such a monoclinic crystalline silicate having a relatively high atomic ratio of silicon to aluminum of at least 100, preferably more than about 200, preferably without using an organic matrix molecule in the crystallization step, can be obtained. In addition, the crystallite size of the monoclinic crystalline silicate can be kept relatively low, typically less than 1 μm, more typically about 0.5 μm, since the starting crystalline silicate has a low crystallite size, which does not increase in subsequent steps of the process. Therefore, since the crystallite size can be kept relatively small, this can lead to a corresponding increase in catalyst activity. This is an advantage over the known crystalline silicate monoclinic catalysts, where usually the crystallite size is more than 1 μm, since they are obtained in the presence of an organic matrix molecule and directly have a high ratio of δ1 to A1, which, in essence, gives larger crystallite sizes.

According to a third preferred embodiment, the dehydration catalyst is a P-modified zeolite (phosphorus-modified zeolite). These phosphorus-modified molecular sieves can be obtained on the basis of ΜΡΙ, ΜΟΚ, ME, clinoptilolite or PEK crystalline aluminosilicate molecular sieves having an initial ratio of δί to A1, preferably from 4 to 500. P-modified zeolites from this recipe can be obtained on the basis of cheap crystalline silicates with a low ratio of δί to A1 (below 30).

As an example, the specified P-modified zeolite is made by a method including in the following order:

the choice of zeolite (mainly with a ratio of δί to A1 from 4 to 500) from H + or ΝΗ., '- forms ΜΡΙ, ME, PEK, ΜΟΚ, clinoptilolite;

the introduction of P under conditions effective for the introduction, mainly at least 0.05 wt.% P;

separation of solid from liquid, if necessary;

an optional washing step or an optional drying step, or an optional drying step followed by a washing step;

calcination stage; the XTO catalyst and the OCP catalyst are the same or different.

Zeolite with a low ratio of δί to A1 is prefabricated with or without direct addition of an organic matrix.

Optionally, a method of manufacturing said P-modified zeolite includes the steps of steaming and leaching. The method consists in steaming followed by leaching. As a rule, it is known to those skilled in the art that steaming zeolites causes aluminum to leave the zeolite framework and remain in the form of aluminum oxides in the pores and on the outer surface of the pores of the zeolite. Such a transformation is known as dealumination of zeolites, and this expression will be used throughout the text. Processing steamed zeolite with an acid solution leads to the dissolution of the aluminum oxide of the outer frame. Such a transformation is known as leaching, and this expression will be applied throughout the text. Then the zeolite is separated, mainly by filtration, and, optionally, washed. A drying step may be scheduled between the filtration and washing steps. After washing, the solution can either be separated, for example, by filtration, from a solid, or evaporated.

P can be introduced by any means or, as an example, according to the method described in US patent 3911041, US patent 5573990 and US patent 6797851.

The catalyst (A1) made from a P-modified zeolite can be a R-modified zeolite itself or it can be a P-modified zeolite made up of a catalyst by combining with other materials that provide additional hardness or catalytic activity to the final catalyst product.

The separation of liquid from solid is predominantly carried out by filtration at a temperature of 0-90 ° C, centrifugation at a temperature of 0-90 ° C, evaporation or equivalent

- 8,020,426 by the method.

Optionally, the zeolite may be dried after separation before washing. Advantageously, said drying is carried out at a temperature of 40-600 ° C., preferably 1-10 hours. Such drying can be performed either under a static condition or in a gas stream. Air, nitrogen or any inert gases may be used.

The washing step can be carried out either during filtration (separation step) with a portion of cold (<40 ° C) or hot water (> 40, but <90 ° C), or the solid can be subjected to an aqueous solution (1 kg of solid 4 l of an aqueous solution) and processed under reverse current conditions of 0.5-10 hours, followed by evaporation or filtration.

The final stage of calcination is carried out mainly at a temperature of 400-700 ° C in a static condition or in a gas stream. Air, nitrogen or any inert gases may be used.

According to a specific embodiment of this third advantageous embodiment of the invention, the phosphorus-modified zeolite is made by a process comprising the following order:

selection zeolite (advantageously with relation to δί A1 from 4 to 500, 4 to 30 in a specific embodiment) of H + or ₄ ⁺ -form IN MH, MEL, OBS, IOC, clinoptilolite;

steaming at a temperature in the range from 400 to 870 ° C 0.01-200 h;

leaching with an aqueous acid solution under conditions effective to remove a substantial portion of A1 from the zeolite;

the introduction of P with an aqueous solution containing a source of P, under conditions effective to introduce predominantly at least 0.05 wt.% P;

separation of solid from liquid;

an optional washing step or an optional drying step, or an optional drying step followed by a washing step;

calcination stage.

Optionally, an intermediate step exists between the steaming step and the leaching step, such as, for example, contacting the silica powder and drying.

Advantageously selected MP1, MEL, OBS, IOC, clinoptilolite (or H + or ₄ ⁺ -form IN MP1, MEL, OBS, IOC, clinoptilolite) has an initial atomic ratio A1 δί to 100 or lower and from 4 to 30 in a specific embodiment, implementation. The conversion to H + or IN ₄ ⁺ form is known, in fact, and is described in US patent 3911041 and US patent 5573990.

Advantageously, the final content of P is at least 0.05% by weight and preferably from 0.3 to 7% by weight. Preferably at least 10% A1 with respect to the starting zeolite MP1, ME, PEK, IOC and clinoptilolite is recovered and removed from the zeolite by leaching.

Then the zeolite is either separated from the washing solution, or dried without separation from the washing solution. Said compartment is preferably carried out by filtration. Then the zeolite is calcined as an example at 400 ° C for 2-10 hours

In the steam treatment step, the temperature is preferably from 420 to 870 ° C., more preferably from 480 to 760 ° C. The pressure is preferably atmospheric pressure, and the partial pressure of water may be in the range from 13 to 100 kPa. The vapor atmosphere preferably contains from 5 to 100 vol.% Steam and from 0 to 95 vol.% Inert gas, preferably nitrogen. Steam treatment is preferably carried out over a period from 0.01 to 200 hours, preferably from 0.05 to 200 hours, more preferably from 0.05 to 50 hours. Steam treatment reduces the amount of tetrahedral aluminum in the crystalline silicate framework by formation of aluminum oxide .

Leaching can be done with an organic acid such as citric acid, formic acid, oxalic acid, tartaric acid, malonic acid, succinic acid, glutaric acid, adipic acid, maleic acid, phthalic acid, isophthalic acid, fumaric acid, nitrile triacetic acid, hydroxyethylene dihydroxyethylene acid, ethylenediaminetetraacetic acid, trichloroacetic acid, trifluoroacetic acid or a salt of such an acid (e.g., sodium salt), or a mixture of two or more of such acids or salts. Other inorganic acids may include an inorganic acid, such as nitric acid, hydrochloric acid, methanseric acid, phosphoric acid, phosphonic acid, sulfuric acid or a salt of such an acid (for example, sodium or ammonium salts), or a mixture of two or more such acids or salts.

The residual content of P is controlled by the concentration of P in an aqueous acid solution containing the source P, the drying conditions and the washing procedure, if any. A drying step may be provided between the filtration and washing steps.

The specified P-modified zeolite can be used as a catalyst. In another embodiment, it can be formulated into a catalyst by combining with other materials that provide additional hardness or catalytic activity to the final catalyst product. The materials that can be mixed with the Modified Zeolite can be various inert or catalytically active materials, or various binding materials. These materials include compositions such as kaolin and other clays, various forms of rare earth metals, phosphates, alumina or alumina sol, titanium dioxide, zirconia, silica, silica or silica sol and mixtures thereof. These components are effective in densifying the catalyst and increasing the strength of the constituted catalyst. The catalyst may be formed into granules, spheres, extruded into other forms, or formed into particles by spray drying. The amount of P-modified zeolite that is contained in the final catalyst product varies from 10 to 90 wt.% Of the total catalyst, preferably from 20 to 70 wt.% Of the total catalyst.

Examples

The analysis of crude bioethanol Table 1. The main characteristics of the crude bioethanol

Crude ethanol Total 8 mg / l <0.25 Total N mg / l twenty Main volatile N mg / l 5 Να mg / l 0.7 Sa mg / l 1.12 Mp mg / l <0.03 Re mg / l <0.04 Si mg / l 0.1 Ζη mg / l 0.04 Alcohol content volume. % at 20 ° C 93 Total acidity g / hl acetic acid 0.37 Esters g / hl 14.2 Acetaldehyde / Acetal g / hl thirty

GC-MS analysis (gas chromatography - mass spectrometry) determined that acetonitrile was present as the N compound in the feed of crude bioethanol.

Example 1

Performed without any purification of ethanol.

The dehydration catalyst is commercially available silicalite (§115 from IOR, §ί / Α1 = 150), which was subjected to dealumination using a combination of steaming with acid treatment to obtain a ratio of δί to Α1 270. Then, dealuminated zeolite was extruded with silica in as a binder to obtain 70% zeolite in the granule. A detailed procedure for the preparation of the catalyst is disclosed in European patent 1194502 B1 (example I).

FIG. 1 and table 2 clearly show a very fast catalyst deactivation in TO§ (flow time) during the processing of crude bioethanol: after 7 hours of operation, C ₂ = yield drops sharply.

After recovery, activity is fully restored using high purity ethanol.

Indeed, tab. 3 shows the activity of the catalyst in the processing of high purity ethanol before processing the crude bioethanol.

Tab. 4 shows the activity of the catalyst in the processing of high purity ethanol after the processing of crude ethanol and reduction of the catalyst.

Comparison of the table. 3 and 4 clearly shows very similar characteristics of the catalyst.

Thus, this means that catalyst deactivation is not irreversible. The start of catalyst deactivation may be due to compounds selectively reacting with the acid sites of the catalyst.

- 10,020,426

Table 2. Product selectivity for the conversion of crude bioethanol on a catalyst

Innings P (bar) T (° C) 5УН8У (Н-1) The conversion of EUN (wt.% CH2) 2 380 7 99.9 2 380 7 95.3 ЕУН / Н ₂ О (95/5) weight. % 2 2 2 2 380 380 380 380 7 7 7 7 90.6 87.3 81.1 88.8 2 380 7 75.0 2 380 7 56.0 ABOUT HER 0.2 1.7 5.3 10.3 19.9 8.0 29.5 38.7 Acetaldehyde 0.2 0.5 0.5 0.6 0.5 0.7 0.6 0.5 ,. Exit on, Oskov '; C;,. „Chui > R! ¹ ** ' '* * ^{G. 1} (wt.% CH2)> * ί, * /. - ¹ '5 - 9 + c Y u u> ? ΐτΈ N * and ¹ ./Dhl-'g· *, '· SY4 0,0 0,0 0,0 0,0 0,0 0,0 0,0 0,0 C2 0.4 0.2 0.2 0.2 0.2 0.4 0.2 0.1 C2 = 93.9 91.0 83.0 74.6 59.0 77.8 43.6 16,2 C3 = thirteen 0.2 0.1 0.1 0.1 0.2 0.1 0.1 C4 + olef. 2,3 0.1 0.9 0.8 0.6 1,1 0.4 0.2 C4 + para. 0.9 0.2 0.1 0.1 0.1 0.2 0.2 0.1 Aromatic 0.2 0,0 0,0 0,0 0,0 0,0 0,0 0,0 Unknown 0.5 0.5 0.4 0.4 0.6 0.5 0.3 0.1 , C ^ jectivity of X, -, ·. · <| B \ C) £ . Already;? JJ Pit wai ! §6y 1, -1¾ SHNI "I® ιβι> hr N4 ". : - ’> "1 me Ex / ' -Arc. ’ Δ - / ¾.) CH4 0,0 0,0 0,0 0,0 0,0 0,0 0,0 0,0 C2 0.4 0.3 0.3 0.3 0.2 0.4 0.3 0.2 C2 = 94.0 95.4 91.7 85,4 72.7 87.7 58.1 28.8 C3 = 1.3 0.2 0.2 0.2 0.2 0.2 0.2 0.2 With 4+ olef. 2,3 1,1 1,0 TO 0.7 1,2 0.6 0.4 C4 + para. 0.9 0.2 0.1 0.2 0.1 0.2 0.2 0.3 Aromatic 0.2 0,0 0,0 0,0 0,0 0,0 0,0 0,0 Unknown 0.5 0.5 0.4 0.5 0.8 0.6 0.5 0.2 Purity C2 (%) 99.63 99.73 99.72 99.68 99.67 99.54 99.53 99.21

- 11,020,426

Table 3. Catalytic characteristics of the catalyst before processing the crude bioethanol

Innings ЕУН / Н ₂ О (95/5) weight. % P (bar) 2 T (° C) 380 \ MN5U (N-1) 7 The conversion of EUN (wt.% CH2) 99.95 ΏΕΕ 0.1 Acetaldehyde 0.25 ί ¹ * Vghodtsayusn9veO. (wt.% CH2) 1 CH4 “ V, ’ϊ’ ·, ' 0,0 C2 0.1 C2 = 96.1 C3 = 0.7 C4 + olef. 2.1 C4 + para. 0.3 Aromatic 0.1 Unknown 0.1 Is it based on C, (wt.%. CH2)? l-p CH4 0,0 C2 0.10 C2 = 96.1 sz = 0.7 C4 + olef. 2.1 C4 + para. 0.3 Aromatic 0.1 Unknown 0.1 Purity C2 (%) 99.90

- 12,020,426

Table 4. Catalytic characteristics of the catalyst after processing of crude bioethanol and reduction of the catalyst

Innings P (bar) T (° C) 1УН8У (Н-1) The conversion of EUN (weight,% CH2) ЕУН / Н2О (95/5) weight. % 1.35 380 7 one hundred 2 380 7 one hundred ϋΕΕ 0,0 0,0 Acetaldehyde 0.39 0.26 CH4 0,0 0,0 C2 0.23 0.22 C2 = 96.4 96.0 sz = 0.4 0.5 C4 + olef. 1,5 1.9 C4 + para. 0.2 0.3 Aromatic OD 0,0 Unknown 0.7 0.6 .¾ '' U ' l * "! ·· ' CH4 0,0 0,0 C2 0.23 0.22 C2 = 96.4 96.1 C3 = 0.4 0.5 C4 + olef. 1,5 1.9 C4 + para. 0.2 0.3 Aromatic od 0,0 Unknown 0.7 0.6 Purity C2 (%) 99.76 99.77

Example 2. Dehydration of ethanol with purification against the stream according to this invention

To remove compounds selectively reacting with the acidic sites of the catalyst, an upstream purification step is carried out.

This purification step involves the hydrogenation of nitrile and aldehyde compounds, thus converting the amphoteric type to basic organic compounds; this stage is achieved on a на -based catalyst under the following operating conditions:

a catalyst based on Νί, LH8U (ΕΐΟΗ) = 12 h ^-1 , H ₂ / EYUN = 3.3 l (n.a.) / l, at ambient temperature and at a pressure of 2 bar;

then the obtained basic compounds are removed by adsorption on an acid adsorbent under the following conditions:

A15 wet sulfonic acid resin, LH8U (ΕΐΟΗ) = 6 h ^-1 , at ambient temperature and pressure.

This purified bioethanol is then sent to the dehydration section using commercially available silicalite (8115 from υΟΡ, δί / Α1 = 150), which was subjected to a dealumination treatment by a combination of steaming with an acid treatment so that a ratio of δί to A1 270 is ensured. Then, the dealuminated zeolite was extruded with dioxide silicon as a binder to obtain 70% zeolite in the granule. A detailed procedure for the preparation of the catalyst is described in European patent 1194502 B1 (example I).

Conditions for the functioning of dehydration:

L8U (YUN) = 7 h ^-1 , a mixture of YUN / H ₂ O 95/5 wt.%, 380 ° C and 400 ° C and at a pressure of 2 bar.

Tab. 5, FIG. 2 and 3 represent the catalytic characteristics of the catalyst in the processing of crude bioethanol in an upstream cleaning section. It turns out that thanks to this purification treatment, the characteristics of the catalyst are very close to those obtained with high purity ethanol.

- 13,020,426

Table 5. The selectivity and conversion of the product during processing of the feed of bioethanol, purified by cleaning against flow

Innings one ABOUT (95/5) weight. % P (bar) 2 T (° C) 380 400 AN8U (H-1) 7 7 The conversion of EUN (wt.% CH2) one hundred one hundred ΏΕΕ 3.6 1.8 Acetaldehyde 0.21 0.23 C based yield (wt.% CH2). , ¹ , _ ^{4 1} * (* * ¹ - ¹⁴ CH4 0,0 0,0 C2 0.26 0.24 C2 = 91.8 93.5 C3 = 0.8 0.9 C4 + olef. 2.1 2,3 C4 + para. 0.4 0.3 Aromatic 0.1 0.1 Unknown 0.6 0.5 Selective basis based on C (wt .'- ° / o CH2) “ ¹ ί {< ί ί * ι ¹ CH4 0,0 0,0 C2 0.26 0.24 C2 = 91.8 93.5 sz = 0.8 0.9 C4 + olef. 2.1 2,3 C4 + para. 0.4 0.3 Aromatic 0.1 0.1 Unknown 0.6 0.5 Purity C2 (%) 99.72 99.74

For the following examples (3 and 4), another crude bioethanol (labeled crude bioethanol 2) was used with the following characteristics:

Table 6. Characteristics of crude bioethanol 2

Crude Bioethanol 2 Total 8 parts per million <0.3 Total N parts per million 0.8 Νη parts per million 0,07 Sa parts per million 0.05 Ζη parts per million 0.16 Si parts per million 0.11 Aldehydes parts per million 378 Esters parts per million 105 Higher alcohols parts per million 1359 Alcohol content volume. % at 20 ° C 93.78

Example 3

Without an ethanol purification section, the catalyst exhibits very fast deactivation: at a pressure of 2 bar, 400 ° C, at L§HU (EH) 7 h ^-1 and using a mixture of EHH / H ₂ O 95/5 wt.%, The dehydration catalyst begins to deactivate after 10 hours of work and after 10 hours the conversion of ethanol decreases from 100

- 14,020,426 to 60 wt.% (Based on C), in addition, the yield of C2 = has the same tendency, changing from 96 to 46 wt.% C (Fig. 4).

Example 4

This experiment shows the advantage of using the improved cleaning section, which is as follows.

This purification step involves the hydrogenation of nitrile and aldehyde compounds, thus converting the amphoteric type to basic organic compounds; this stage is achieved on a на -based catalyst under the following operating conditions:

a catalyst based on Νί, LH§U (ΕΐΟΗ) = 2.4 h ^-1 , Η ₂ / ΕΐΟΗ = 5.6 l (n.a.) / l, at ambient temperature and at a pressure of 15 bar;

then the obtained basic compounds are removed by adsorption on an acid adsorbent under the following conditions:

Η-Υ zeolite sorbent (δί / Α1 2.7), LН§У (ΕΐΟΗ) = 1.2 h ^-1 , at ambient temperature and at a pressure of 15 bar;

ethanol is then passed through a combination of a strongly anionic ion exchange resin and a strongly acidic ion exchange resin so as to remove residual impurities that impair the activity of the dehydration catalyst.

When processing with purification of the aforementioned crude bioethanol, the results of dehydration carried out under the following operating conditions: pressure 2 bar, 400 ° C, at L§NU (ΕΐΟΗ) 7 h ^-1 and using a mixture of ΕΐΟΗ / Η ₂ Ο 95/5 wt.% are presented in table. 7.

Very good catalytic characteristics were obtained, and the dehydration catalyst showed very good stability over a 120 hour catalytic test.

Table 7. Product selectivity and conversion during processing of a feed of bioethanol purified in an improved upstream purification section

Innings EYUN / ЩО (95/5) weight. % P (bar) 2 T (° C) 400 \ UN5U (H-1) 7 The conversion of EUN (wt.% CH2) one hundred ΌΕΕ 0,0 Acetaldehyde 0.01 VCxOd on / on the basis of C (ve ^ .- ^ o'CE ^ U,. • '^!; Έ 'ιΛΕ ^: - // 7 ...... CH4 .......... '' ' 0,0 C2 0.14 C2 = 96.6 sz = 0.7 C4 + 1.7 Aromatic 0,0 -Μ? ',, CH4 0,0 C2 0.14 C2 = 96.6 sz = 0.7 C4 + 1.7 Aromatic 0,0 Purity C2 (%) 99.86

CLAIM

Claims (11)

(1) preparing a reaction zone (C) comprising an acid type catalyst; 1. The method of purification of alcohol other than tert-butyl alcohol, during which: 2. The method according to claim 1, where the impurities are selected from the group comprising nitriles, aldehydes, ketones, carboxylic acids, esters of carboxylic acids, amides and the corresponding thio compounds and imines. (2) preparing a reaction zone (B) comprising an adsorbent material and / or a combination of sorbent materials; 3. The method according to any one of the preceding paragraphs, where only part of the alcohol stream of step (3) is processed in step (4), mixed with the untreated part and introduced into the reaction zone (C). (3) preparing an alcohol stream comprising impurities; 4. The method according to any one of the preceding paragraphs, where, before step (4), the alcohol stream of step (3) is introduced into the reaction zone (A), including a hydrogenation catalyst, and brought into contact with the specified catalyst in the presence of hydrogen under conditions effective (ί ) to convert part or all of the impurities to modified impurities that can remain on the acidic adsorbent material of the reaction zone (B), and / or (ίί) to convert part or all of the impurities to modified impurities that do not adversely affect the catalyst -type reaction zone (C). (4) introducing the alcohol stream (3) into the reaction zone (B) and bringing said stream into contact with the sorbent material (s) under conditions effective to reduce the amount of impurities adversely affecting the acid type catalyst of the reaction zone (C); 5. The method according to claim 4, where only part of the alcohol stream of step (3) is treated in the reaction zone (A), mixed with the untreated part and introduced into the reaction zone (B). (5) sending the alcohol of step (4) to the reaction zone (C); 6. The method according to any one of claims 1 to 3, where the acidic adsorbent material in the reaction zone (B) works in the same way as a hydrogenation catalyst. (6) optionally introducing one or more reagents (K) into the reaction zone (C); 7. The method according to claim 6, where there is no zone (A) and in the specified zone (B) the alcohol stream is brought into contact with the specified catalyst in the presence of hydrogen under conditions effective (ί) to convert part or all of the impurities into modified impurities capable of stay in the specified catalyst of the reaction zone (B), and / or (ίί) to convert part or all of the impurities into modified impurities that do not adversely affect the acid type catalyst of the reaction zone (C). (7) operate the specified reaction zone (C) under conditions effective for the esterification or dehydration of alcohol. 8. The method according to claim 7, where only part of the alcohol stream of step (3) is treated in the reaction zone (B), mixed with the untreated part and introduced into the reaction zone (C). 9. The method according to any one of the preceding paragraphs, where in the reaction zone (C) provide for the dehydration of alcohol. 10. The method according to any one of claims 1 to 8, wherein the olefin is esterified in the reaction zone (C), the reagent (K) of step (6) being the specified olefin. 11. The method according to any one of claims 1 to 8, wherein alcohol is self-esterified in the reaction zone (C).